Custom SQL Functions
The SQL Engine can extend the SQL functions' set, defined by the ANSI-99 specification, via the addition of custom SQL functions written in Java.
A custom SQL function is just a public static method marked by the @QuerySqlFunction annotation.
@QuerySqlFunction
public static int sqr(int x) {
return x * x;
}The class that owns the custom SQL function has to be registered in the CacheConfiguration.
To do that, use the setSqlFunctionClasses(…) method.
// Preparing a cache configuration.
CacheConfiguration cfg = new CacheConfiguration("myCache");
// Registering the class that contains custom SQL functions.
cfg.setSqlFunctionClasses(SQLFunctions.class);
IgniteCache cache = ignite.createCache(cfg);Once you have deployed a cache with the above configuration, you can call the custom function from within SQL queries:
// Preparing the query that uses the custom defined 'sqr' function.
SqlFieldsQuery query = new SqlFieldsQuery("SELECT name FROM myCache WHERE sqr(size) > 100");
// Executing the query.
cache.query(query).getAll();© 2024 GridGain Systems, Inc. All Rights Reserved. Privacy Policy | Legal Notices. GridGain® is a registered trademark of GridGain Systems, Inc.
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